Dead-center device



.July 19 1927.

J. H. TOWERS DEAD CENTER DEVICE Filed May 15, 1926 1 ove c m ead uters.

Patented July 19, 1927.

UNITED STATES?! fj was Q1:eater s ve omen-entrust neuron. j

a lication mm, :15, 1326. Serial in. 100,401.

'Dh inven n relate to an mpr ved m ehani al movement designed to e mp oy f r converting reciprocatory mov m n n o mov men f o ation, th :obie of th in-' vention being to provide an assemblage of han ca e ments whic w ll coop ate o The inventi n is applic ble r use in c nnection with steam engines, ga eng n indmi l-s, hand operated devices, r in any nelation wherein it'is desired, to overc me dead c nters. V i

Al i ustrative ,e nbodi, ent f th i en i ie is hown in the ac mpanying rawi gs in which Figu 1 i a side view of the dev e fis ewn connected atone ,end to ;a reciprocating piston and at the other tea wheel. i

Figure 2 is an end view of the same.

Figu e 3 is a t agme ta y vi w, imilar to Figure 1, bu sh wing a imedific t n I th rawings h re erence n mera 1 d n s a su tab e fixed ba o suppo the mi a .11 d n t s a w ee-. ota ing about fixed center 12 and-th numeral 13 ote a fix d ylinder h v ng a r c p o at g Pis 14 provided with a piston rod 15. It is desired to transform the reciprocatory movementof the piston rod .15 into rotary movement of the wheel 11 by a suitable assemblage of mechanical elements which are so related that they effectively overcome dead centers. 7

Pivotally connected to the rod 15 as at 16 is a connecting rod 17 ,which atits opposite end is pivoted as at 18 to the vertical arm 19 of a T crank, the horizontal arm 20 )1? which is connected to the fly wheel 11 by means of the crank pin 31. The T crank is pivoted at 21 to an oscillating rocker arm 22 which is pivoted as at 23 to the stationary support 10, as shown. A suitable spiral spring 24 connects the fixed pivot 23 to the oscillating pivot 18 at the juncture of the crank arm 22 and the arm 19 of the T crank. The rocker arm 22 is adapted to swing to and fro as a pendulum, oscillating about the fixed pivot 23, and carries with it the oscillating pivot 21 which swings in the arc of a circle, indicated by the arrows.

Assuming now that the mechanism is in the position shown in full lines in Figure 1, and that the spring 24 is under tension, the iston rod 15 is moved to the right in the direction of the arrow. Due to the down- Ward pressure produced by the spring 24 on the pivot-21, a movement of the wheel 11 in counterclockwise direction, as indicated by h ar ow results, and the crank pin 31 is carried pashthe dead center position, due to h a tion of the pri g 24 wh ch is op r t r at h m m n whe t e p o b n its reversestroke. One position which would normally be a dead center position, if the n fl e ab en is indica ed in the dotted lines, this being likewise the position in which the piston 1 1 has reached its extreme lim tto the right and eg t ev rs HQWever, due to the energy. which has been s o d n he sp sflt, th hee i s app ne tth d en er.pesitiemth for of th spr n b in g eat s a he tim t t rse app i y the pis on i least Th Wheel there-fore continues to rotate uni erm c' in we di ct on, e ng a ie p s each dead center the spring. v

, ()bviously it the :torce operating upon the n e 21 we v rs d, r in ta c i a mp e s on spri g were sub t tu d to e p ine; 2 the d rect o o m ement at the e 11 weu d e reve e thm th act on an overcoming dead center would he the same as be or i v a I Likewi e, it wi b tunne a Wheret reeipm etm tome is snn ed'. o theilewer end of the crank," as where the link 17 is connected to the lower end of the arm 19, direction of rotation of the wheelll is reverse to that in which the force is applied above the pivot 21. In other words, the direction of rotation maybe reversed either by reversing the direction of force of the spring 24 on the crank arm 19 or by changing thepoint of application of the recipro eating force from a position above to a position below the pivotconnecting the rocker arm with the T crank.

A modification of theinvention is indicated in Figure 3, wherein a'piston' and cylinder, using compressed air, is substituted for the spring 2 1. The'wheel 11, and the mechanism for producing reciprocating movement are omitted in this figure, as it is understood that they operate in the manner described in connection with Figure 1. In

position by the c i of Figure 3, the reference numeral 19 indicates downward pressure upon the pivot 21' acting at an angle to the arm 20, a piston and cylinder may be employed by means of which compressed air or other fluid, performs the function of the spring. As shown, a cylinder 30, having air inlets 31 and 32 is provided with a piston 33, the rod 34 of Which is connected by means of a suitable crank-arm 35 to the upper end of the T crank, as at 18.

The operation of this device is the same as that described in connection With Figure 1. In order to reverse the direction of movement of the Wheel (not shown) it is only nece.:sary to reverse the direction of the pressure acting upon the pivot 21, this being accomplished by introducing compressed fluid above or below the piston 33 as desired.

Many changes maybe resorted to Without departing from the spirit of the invention. For example, the T crank is not essential to the operation of the device, as any crank having arms set at angles to each other may be employed in a similar relation. Likewise, in place of the spring 24 or the compressed air cylinder, any means may be employed which Willproduce a pressure upon the oscillating pivot, which pressure acts at an angle to the arm of the crank Which is attached to the Wheel or rotary element.

What I claim is l. A device for overcoming dead centers comprising in combination with a fixed pivot, a rocker arm oscillating about said, fixed pivot, a rigid right angle crank pivotally connected to the oscillating end'of the rocker arm, a rotary element connected to one end of said rigid crank, and a source of power operating another arm at an angle thereto, and means for applying pressure to said crank, the direction of pressure determining the direction of movement of the rotary element.

2. A mechanical movement for translating reciprocatory into rotary movement, designed to overcome dead centers, comprising a rocker arm oscillating about a fixed pivot, a rigid" crank having arms set at angles to each other, one arm being connected to a 1'0- tary element, said crank being pivoted at the juncture of the arms thereof to the oscillat ing end of the rocker arm, and means for exerting pressure upon the oscillating pivot of said crank.

3. A device for overcoming dead centers, comprising a fixed pivot a rocker arm oscillating about said fixed pivot, abell crank pivotally connected to the oscillating end of the rocker arm, one arm of said bell crank being connected to a rotary element and the other arm adapted to be operated from a suitable source of power, and resilient means interposed between the fixed pivot of said rocker arm and one end of said bell crank.

4. A mechanical movement for translating reciprocatory into rotary movement or vice versa comprising fixed pivot, a rocker arm oscillating about said fixed pivot, a bell crank pivotally connected to the oscillating end of the rocker arm, one end of said bell crank being connected to a reciprocatory ele ment and the other to a rotary element, and a spring connecting the fixed pivot of said rocker arm to one end of said bell crank.

In testimony whereof I .atfix my signature.

JOHN H. TOWERS. 

